1. Field of the Invention
This invention broadly relates to telecommunications. More particularly, the present invention relates to priming sequences for network managed fractional T1 or E1 digital service units (DSUs). For purposes herein, the term "DSU" will be understood to encompass a channel service unit (CSU).
2. State of the Art
Among the well-defined standards of the telecommunications industry which are commonly tariffed by the telephone companies are the T1 and E1 telecommunications signals. A T1 telecommunications signal is basically a 1.544 MHz digital telecommunications signal which utilizes a frame of one hundred ninety-three bits. Of the one hundred ninety-three bits of the frame, one hundred ninety-two bits are used to transmit twenty-four 64 kbps DS0 bytes, while the remaining bit is used for framing and overhead purposes. An E1 telecommunications signal is a 2.048 MHz signal which utilizes frames of two hundred fifty-six bits, with thirty-two DS0 (TS0) bytes, but does not include a framing/overhead bit. Instead, framing information is carried in time slot 0 (TS0) and overhead in time slot 16 (TS16) of the E1 signal.
In many common applications it is desired that a master DSU which is coupled to the digital network via a T1 or E1 line be able to communicate with a plurality of remote DSUs which may be similarly coupled to T1 or E1 lines. In fact, in a managed network, it is desirable for the master DSU to have a means to be able to configure and manage those remote DSUs. In managing the remote DSUs, a diagnostic channel must be established and utilized. Thus, presently, in order to manage a remote DSU, the master DSU must already be in established contact with the remote DSU as there is no expedient mechanism for finding the diagnostic channel in the bundle of DS0s where the remote DSU is not configured. For new remote installations, it is therefore required that a technician visit the installation site and establish contact with the network manager or master DSU according to known techniques. However, clearly, it would be advantageous to be able to manage a remote DSU without such manual intervention.